I am doing a painting project for the first time too.
I know if you want a smooth surface, you can use 2 modest coats of polyester resin, such as Sig finishing resin. You can sand between coats, but make sure you sand thoroughly before painting. Remember that 90% of the finish's appearance is a direct reflection of the surface prep. I learned this painting cars.
I don't think you need primer if painting resin-treated wood, but I am new to this as well. I could be wrong.
As far as paint, I am looking for advice myself, so I am no help here. I would opt for using an airbrush over a spray can. More control and more consistent droplet size of the paint
Anyway, good luck.
Stu
